**UNITED STATES ENVIRONMENTAL PROTECTION AGENCY** NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY

2000 TRAVERWOOD DRIVE ANN ARBOR, MI 48105
- 2498

OFFICE OF AIR AND RADIATION February 18 , 20 14 MEMORANDUM SUBJECT: Revised PBMS Flow Charts from April 18, 2013 Meeting with American Petroleum Institute (API) Test

Methodologies Workgroup FROM: Joe Sopata, Chemist

USEPA/ OAR/OTAQ/CD/FCC TO: EPA Docket # EPA
- HQ
- OAR
- 2011
- 0135 This me mo corrects the flow charts that were provided to the docket documenting a meeting held on April 18, 2013 between representatives of API Test Methodologies Workgroup an d the United States Environmental Protection Agency ( EPA ) to discuss EPA’s Performance Based Analy tical Test Method Appr oach included in the proposed rule entitled, “Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards”. The meeting attendees from APITest Methodologies Workgroup included David L ax (API), Janice Raburn (BP), Kathry n Brtko (BP), Sonia Bain (Marathon), John Rizzo (Marathon), Richard Stanley , Alex L ao, Frank Disanzo (ExxonMobil), Barbara Schroeder (Shell), Al Verstuft (Chevron) and Kishore Nadkarni, , and from EPA included Joe Sopata , Robert Anderson, Winifred Okoye, and John Weihrauch
. The discussion topics during this meeting included background, proposed qualification criterion, statistical quality control requirements, implementation dates and Agency approval options which were presented in detail in the preamble and regulations of the Tier 3 proposal. In a ddition, m eeting attendees from the API Test Methodologies Workgroup requested EPA provide flow chart examples of qualification requirements for Absolute Fuel Parameter s and Method Defined Fuel Parameters. During the commentperiod for the proposed rulemaking, API and AFPM provided editorial comments for the Absolute Fuel Parameter flow chart and

requested that these flow charts be corrected in the docket for the Tier 3 final rulemaking
. In addition, during th e comment period for the proposed rulemaking, several comments were made on the criterion for the reference installation of the designated test method as well as the precision criterion for method defined fuel parameters in which EPA agreed. Thus the flow chart example for method defined fuel parameter was corrected to reflect the changes applicable to method defined fuel parameters in the Tier 3 final rule. The corrected flow charts for both the Absolute Fuel Parameter and Method Defined Fuel Parameter are attached to this memorandum but are not intended to cover all aspects of the Performance Based Anal yt ical Test Method Approach requirements. EPA encourage s review of both the Tier 3 final rule’s preamble and regulations for details not covered in these flow charts.

## Flow Chart **Example :**  **Absolute Fuel Parameter (Absolute)**  **- Sulfur in Gasoline**  Note : F uel parameters categorized as “ Absolute ” are s ulfur in g asoline and s ulfur in b utane , besides sulfur in diesel fuel ( VCSB

– Voluntary Consensus Standards Body )

YES YES

NO NO NO

YES Is Alternative Test Method a Voluntary Consensus Standard Body (VCSB Method)? **Precision**
- the maximum allowable standard deviation of 20 test results on a 10 ppm gasoline would be 0.95 ppm. **Accuracy**

– the average of 10 consecutive results on a 1
- 10 ppm gravimetric sulfur standard cannot differ by more than 0.71 ppm from th e ARV of the standard and the average of 10 consecutive results on a 10
- 20 ppm gravimetric sulfur standard cannot differ b y more than 1.00 ppm from the ARV of the standard
. Method Qualified

Lab determines if ASTM D6708 reveals that sample
- specific biases cannot be determined as random?
Method Disqualified. Method Disqualified

## Flow Chart E **xample :**  **Method -**  **Defined Fuel**  **Parameter (Method**  **- Defined)** 

**Aromatics in Gasoline:** Note : A ll other fuel parameters besides sulfur in diesel fuel, sulfur in gasoline , and sulfur in butane currently designated in our gasoline and diesel fuel programs are Method
- D efined ( VCSB

– Voluntary Consensus Standards Body )

YES NO

YES NO YES NO Obtain use of a Reference Installation of Designated Test Method (DM): 1) DM near mi ddle distribution of within the middle 50% of the distribution of measurements for 3 out of 5 exchanges of either the industry

or commercially

available monthly I LC C program for at least five months
. 2) DM has been shown to be in statistical control for a period of 5 months
. Precision
- the maximum allowable standard deviation of 20 test results on a 32 volume percent aromatics gasoline would be 1.11 volume percent
. Is Alternative Test Method a Voluntary Consensus Standard Bod y (VCSB) Method?

VCSB determines if use of ASTM D6708 yields a null result compared to designated test method (DM)?( ****** )
. Lab determines if ASTM D6708 reveals that sample
specific biases cannot be determined as random?

Use Alternative Test Method result w/o correlation. VCSB uses

ASTM D6708 to determine correlation equation to DM. Method Disquali fied

. Same as ****** but

Lab also determines if the cross method reproducibility (Rcm) is ≤ 70% of published R of DM.